TY - JOUR A1 - Rudolph-Mohr, Nicole A1 - Vontobel, Peter A1 - Oswald, Sascha Eric T1 - A multi-imaging approach to study the root-soil interface JF - Annals of botany N2 - Background and Aims Dynamic processes occurring at the soil-root interface crucially influence soil physical, chemical and biological properties at a local scale around the roots, and are technically challenging to capture in situ. This study presents a novel multi-imaging approach combining fluorescence and neutron radiography that is able to simultaneously monitor root growth, water content distribution, root respiration and root exudation. Methods Germinated seeds of white lupins (Lupinus albus) were planted in boron-free glass rhizotrons. After 11 d, the rhizotrons were wetted from the bottom and time series of fluorescence and neutron images were taken during the subsequent day and night cycles for 13 d. The following day (i.e. 25 d after planting) the rhizotrons were again wetted from the bottom and the measurements were repeated. Fluorescence sensor foils were attached to the inner sides of the glass and measurements of oxygen and pH were made on the basis of fluorescence intensity. The experimental set-up allowed for simultaneous fluorescence imaging and neutron radiography. Key Results The interrelated patterns of root growth and distribution in the soil, root respiration, exudation and water uptake could all be studied non-destructively and at high temporal and spatial resolution. The older parts of the root system with greater root-length density were associated with fast decreases of water content and rapid changes in oxygen concentration. pH values around the roots located in areas with low soil water content were significantly lower than the rest of the root system. Conclusions The results suggest that the combined imaging set-up developed here, incorporating fluorescence intensity measurements, is able to map important biogeochemical parameters in the soil around living plants with a spatial resolution that is sufficiently high enough to relate the patterns observed to the root system. KW - Roots KW - soil-root interaction KW - root distribution KW - Lupinus albus KW - lupin KW - pH dynamics KW - oxygen dynamics KW - soil water distribution KW - rhizosphere KW - fluorescence imaging KW - neutron radiography Y1 - 2014 U6 - https://doi.org/10.1093/aob/mcu200 SN - 0305-7364 SN - 1095-8290 VL - 114 IS - 8 SP - 1779 EP - 1787 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Estendorfer, Jennifer A1 - Stempfhuber, Barbara A1 - Haury, Paula A1 - Vestergaard, Gisle A1 - Rillig, Matthias C. A1 - Joshi, Jasmin Radha A1 - Schröder, Peter A1 - Schloter, Michael T1 - The Influence of Land Use Intensity on the Plant-Associated Microbiome of Dactylis glomerata L. JF - Frontiers in plant science N2 - In this study, we investigated the impact of different land use intensities (LUI) on the root-associated microbiome of Dactylis glomerata (orchardgrass). For this purpose, eight sampling sites with different land use intensity levels but comparable soil properties were selected in the southwest of Germany. Experimental plots covered land use levels from natural grassland up to intensively managed meadows. We used 16S rRNA gene based barcoding to assess the plant-associated community structure in the endosphere, rhizosphere and bulk soil of D. glomerata. Samples were taken at the reproductive stage of the plant in early summer. Our data indicated that roots harbor a distinct bacterial community, which clearly differed from the microbiome of the rhizosphere and bulk soil. Our results revealed Pseudomonadaceae, Enterobacteriaceae and Comamonadaceae as the most abundant endophytes independently of land use intensity. Rhizosphere and bulk soil were dominated also by Proteobacteria, but the most abundant families differed from those obtained from root samples. In the soil, the effect of land use intensity was more pronounced compared to root endophytes leading to a clearly distinct pattern of bacterial communities under different LUI from rhizosphere and bulk soil vs. endophytes. Overall, a change of community structure on the plant-soil interface was observed, as the number of shared OTUs between all three compartments investigated increased with decreasing land use intensity. Thus, our findings suggest a stronger interaction of the plant with its surrounding soil under low land use intensity. Furthermore, the amount and quality of available nitrogen was identified as a major driver for shifts in the microbiome structure in all compartments. KW - Dactylis glomerata KW - land use change KW - endophytes KW - rhizosphere KW - soil microbiome KW - biodiversity Y1 - 2017 U6 - https://doi.org/10.3389/fpls.2017.00930 SN - 1664-462X VL - 8 PB - Frontiers Research Foundation CY - Lausanne ER -